(a) Field of the Invention
The present invention relates to a blood vessel graft and a graft introducer, and more particularly, to a graft introducer that can easily guide a blood vessel graft into a blood vessel, and to such a blood vessel graft that is reduced in its diameter when it is contracted, thereby making it possible to minimize inner and outer diameters of the introducer so that the introducer can be easily inserted into the weakened blood vessel.
(b) Description of the Related Art
As an example, an aneurysm is an abnormal blood-filled dilatation of a blood vessel, and especially an artery, resulting from disease of the vessel wall. It is a very dangerous malady, such that the vessel wall may be broken when the blood pressure within the blood vessel is increased above a predetermined level.
Such an aneurysm is generally cured through a surgical operation. However, for a patient to whom the surgical operation cannot be applied, a blood vessel graft has been developed. But since an introducer for locating the graft in the blood vessel has a diameter larger than 6 mm, the blood vessel should be locally opened through surgery, potentially causing complications. Furthermore, if the blood vessel is complicatedly curved, it is very difficult to dispose the graft in the blood vessel. Therefore, a punching operation method has been developed and used.
In the punching operation method, a surgical operation for opening the blood vessel is not performed, but a minute hole is formed in the artery, and the introducer is inserted into the artery through the minute hole. The blood vessel graft is then disposed in the weakened blood vessel by way of the introducer.
To use such a punching operation method, it is required that the inner and outer diameters of the graft introducer be less than, for example, 4 mm and 4.5 mm, respectively. In addition, the diameter of the graft when it is contracted should be less than the inner diameter of the introducer so that it can be inserted into the introducer.
The conventional graft introducer includes an insertion tube into which the blood vessel graft is inserted, and a pusher for pushing the inserted graft out of the insertion tube. The blood vessel graft includes a graft main body that is introduced into the blood vessel, and self-expandable stents mounted inside of each end of the main body to maintain the shape of the blood vessel when it is disposed in the blood vessel.
However, in the conventional blood vessel graft, since the self-expandable stents are each mounted inside an end of the main body, the graft main body and the stents overlap, increasing the diameter of the graft when it is contracted. This results in increasing inner and outer diameters of the introducer into which the blood vessel graft is inserted.
The present invention has been made in an effort to solve the above described problems, and it is an object of the present invention to provide a graft introducer that can easily guide a blood vessel graft into a blood vessel, and to such a blood vessel graft that is reduced in its diameter when it is contracted, thereby making it possible to minimize inner and outer diameters of the introducer so that the introducer can be easily inserted into the weakened blood vessel.
To achieve the above object, the present invention provides a blood vessel graft having a front side and a rear side in a lengthwise direction, the blood vessel graft comprising:
a flexible blood vessel graft main body to be disposed within a blood vessel to prevent blood pressure from being applied to a weakened blood vessel, the flexible blood vessel graft main body having a front end and a rear end;
a first stent member having a front end and a rear end, the rear end of the first stent member being connected to the front end of the flexible blood vessel graft main body with a gap between the rear end of the first stent member and the front end of the flexible blood vessel graft main body to avoid overlapping the blood vessel graft main body and the first stent member; and
a second stent member having a front end and a rear end, the front end of the second stent member being connected to the rear end of the flexible blood vessel main body with a gap between the front end of the second stent member and the rear end of the flexible blood vessel main body to avoid overlapping the blood vessel graft main body and the second stent member.
Preferably, the first stent member has an identical structure to that of the second stent member. A diameter of the second stent member when the second stent member is contracted is smaller than that of the first stent member.
Each of the first and second stent members comprise a plurality of reference turns each having a unit member which has a zigzag shape, and having a plurality of straight sections and a plurality of bending points that are interlocked with those of an adjacent reference turn so as to provide a mesh-structure. Each of the first and second stent members further comprise an overlapped member twisted along the straight sections.
The second stent member is formed of a wire having a diameter of less than that of the first stent member. The first and second stent members are connected to each other by connecting bars, each of the connecting bars being formed of wires twisted with each other more than twice.
The rear end of the first stent member is connected to the front end of the flexible blood vessel graft main body by a connecting member, and the gap between the rear end of the first stent member and the front end of the flexible blood vessel graft main body is over a predetermined length of about 3 mm.
The front end of the second stent member is connected to the rear end of the flexible blood vessel main body by a connecting member, and the gap between the front end of the second stent member and the rear end of the flexible blood vessel main body is over a predetermined length of about 3 mm.
According to another aspect, the present invention provides a graft introducer for disposing a blood vessel graft in a blood vessel, the blood vessel graft having a main body and first and second stents, each connected to an end of the main body, the graft introducer comprising:
an insertion tube member into which the blood vessel graft main body and the first stent member are inserted in a state where they are contracted;
a first pusher member into which the second stent member is inserted in a state where it is contracted, the first pusher member being movably inserted into the insertion tube member to push the first stent member and the blood vessel graft main body out of the insertion tube member; and
a second pusher member into which a catheter passing through the introducer is inserted, the second pusher member being movably inserted into the first pusher member to push the second stent member inserted in the first pusher member out of the insertion tube member, thereby disposing the blood vessel graft in the blood vessel.
The insertion tube member is formed having an outer diameter of less than 4.7 mm and an inner diameter of less than 4 mm so that it can be easily inserted in the blood vessel, and the blood vessel stent and the first pusher member can be easily inserted therein.
The first pusher member is formed having an outer diameter of less than 3.9 mm and an inner diameter of less than 3.4 mm so that it can be easily inserted into the insertion tube member, and the second stent member can be easily inserted therein.
The second pusher member is formed having an outer diameter of less than 2.9 mm and an inner diameter of less than 1.6 mm and is made of a hard material so as to be movable in the first pusher member and to be easily pushed toward a front end of the insertion tube member.